In high-speed continuous form ink jet printing, it is common to create sheets from multiple, independent color planes (e.g., C, M, Y, K) using any one of ink or toner to mark the physical print medium. Thus, it is critical that each of these color planes be printed on the correct sheet and in the correct position to provide the desired output. Similarly, if the printer is configured in a tandem duplex arrangement, the front and back of the sheet must also be in the correct position.
The print data for each of these independent color planes is created inside a rasterizer and forwarded to respective physical ink jets responsible for that particular color. A problem with any one of the independent color planes affects the entire sheet output. Therefore, a barcode is printed at a specific location on the paper for verification by optical scanners.
Because at high speeds scanning time may be too short to check multiple barcodes on one sheet, a common method to accomplish the check is to rotate the independent color planes while printing (e.g., print a ‘K’ barcode on the first page, an ‘M’ barcode on the second page, etc.). As a result, all color planes are checked within a short time period. When a problem with a barcode is detected, an operator may inspect the printed output to see what color has failed in order to trouble shoot the physical hardware path (cards, cables, drivers, ink jets).
However, simple operator inspection to determine which color has failed becomes impossible when the colors are the same. For instance, in three engine tandem printing with the third engine includes two color planes of black Magnetic Ink Character Recognition (MICR) ink, or two color planes of black ink in monochrome engines. Accordingly, in such applications it is not possible to determine which physical hardware path has failed simply by inspecting the print output.
Moreover, for a new printer model made from a 4 channel (CMYK) printer that has been converted to two channels of black (monochrome) and two channels of black MICR ink, there is an urgent need to be able to determine which color plane has failed when a barcode detection error (e.g., mismatch in position) occurs.
Without knowing which path has failed (and these failures tend to be intermittent), operators may be faced with the time consuming task of swapping many unnecessary parts in order to isolate the failing component.
Accordingly, a mechanism to identify the origin of data from identical color print channels is desired.